Here are ten tips to help you keep an eye out for the rip-off merchants.

If it seems too good to be true, it probably is: This holds for everything in life, but especially for eBay. Things that seem too cheap are usually too cheap for a reason - it might be a complete scam, or the items might just be of extremely poor quality. Investigate before you go further.

Know the value of what you want to buy: There are people on eBay who regularly bid such high prices for used cameras that they might as well have gone out and bought them brand new. Check around for prices first.

Only bid on real things: eBay has plenty of people who are trying to sell all sorts of schemes and scams. It is never worth bidding for these, no matter how cheap they might be.

Don't do anything outside eBay: Occasionally people will ask you to send them money outside eBay, to avoid the fees eBay charges sellers. Any money you send this way is entirely insecure - don't do it.

Be careful where you send payment: People may hack into others' accounts, and ask you to send payment to addresses that eBay has not confirmed as belonging to that account - you might send your money and receive nothing in return.

Look out for sellers who suddenly change what they sell: Sellers can look like they've made lots of transactions, when really they've never sold anything of worth. If they suddenly start selling $1,000 televisions, steer clear - the chances are they're planning to run off with the money.

Beware the shill bidder: If someone who doesn't seem to have bought anything before is constantly outbidding you on a certain item, be suspicious. It might be a seller 'shill bidding' to force up his item's price.

Don't use the seller's escrow service: If an escrow service is recommended to you by a seller, it could well be owned and run by them - and they're quite likely to keep your money and send you nothing.

Pay electronically: You are more likely to be able to recover any losses if you pay using a credit card instead of sending out cheques and money orders - these low-tech payment methods can't be tracked as easily.

Buy from reputable sellers: Each seller has a number next to their name, which is their feedback rating. The higher this rating, the more you can trust them.